Succinonitrile-Regulated In Situ Poly(1,3-dioxolane) Gel Polymer Electrolytes for High-Performance Lithium Metal Batteries

Abstract

In situ polymerized poly(1,3-dioxolane) (PDOL)-based gel polymer electrolytes (GPEs) show great potential for lithium metal batteries (LMBs) due to their excellent interfacial wettability and fast ion transport. However, limited ion transport pathways and unstable Li+ solvation structures in conventional PDOL systems still hinder electrochemical performance. Here, a PDOL/SN in situ gel polymer electrolyte was constructed by incorporating SN (high dielectric constant, weak coordination ability), and the effect of SN content on electrolyte structure and Li+ transport was systematically investigated. The results demonstrate that an appropriate SN amount enhances polymer segment mobility and constructs a synergistic “ether oxygen–nitrile group” ion transport network. Radial distribution function (RDF) analysis reveals that SN optimizes the Li+ solvation structure via weak nitrile–Li+ coordination, promoting Li+ dissociation and migration while preserving the PDOL-dominated coordination structure. The optimized PS2 electrolyte delivers an ionic conductivity of 3.39 × 10–3 S cm–1 and a Li+ transference number of 0.71 at 25 °C. Moreover, the LFP/PS2/Li cell retains 87.98% capacity after 550 cycles at 1C. This work elucidates the structure–property relationship of SN-regulated Li+ transport and solvation in PDOL systems, offering a strategy for designing high-performance in situ GPEs.